What does the excess reactant determine?

The reactant that produces a larger amount of product is the excess reagent. To find the amount of remaining excess reactant, subtract the mass of excess reagent consumed from the total mass of excess reagent given.

How do you solve for excess reactant?


  1. Write the chemical equation.
  2. Calculate the moles of product from the first reactant.
  3. Calculate the moles of product from the second reactant.
  4. Identify the limiting reactant and the excess reactant.
  5. Calculate the mass of excess reactant used up.
  6. Calculate the mass of unused excess reactant.

What is the excess reactant in photosynthesis?

Carbon dioxide concentration Carbon dioxide – with water – is one of the reactants in photosynthesis. If the concentration of carbon dioxide is increased, the rate of photosynthesis will therefore increase. Again, at some point, a factor may become limiting.

Why is excess reactant important?

A good way to ensure that one reactant fully reacts is to use an excess of the other reactant. The other reactant becomes a limiting factor and controls how much of each product is produced. While using excess reactants can help to increase percentage yields, this is at the expense of atom economy.

Which substance is excess reactant?

limiting reagent
In a chemical reaction, reactants that are not used up when the reaction is finished are called excess reagents. The reagent that is completely used up or reacted is called the limiting reagent, because its quantity limits the amount of products formed.

Is it possible to have no limiting reactant?

When there is no limiting reactant in a chemical equation, that means the reaction goes to completion. All of the reactants are used. Also, there is no excess. However, this is very unlikely to occur.

Which substance is in excess?

The reactant in excess, also known as the excess reagent, is the amount of chemical remaining after a completed reaction. It is governed by the other reactant, which is completely used and can therefore cannot react. When you know the reactant in excess, you can work out the final amounts of both product and reactant.

What is an excess reactant Quizizz?

excess reactant. limiting reactant. 120 seconds. Q. A reactant that is totally consumed during a chemical reaction, limits the extent of the reaction, and determines the amount of product.

Can the limiting reactant be present in excess?

It’s called the limiting reactant because it gets used up first in a chemical reaction. This results in the smallest amount of reactant in a chemical equation. Excess is the opposite, having the largest amount. In a reaction where there is only one product or one reactant, limiting reactants and excess do not “exist”.

How to find the excess reactant in a reaction?

The excess reactant may be found using the balanced chemical equation for a reaction, which gives the mole ratio between reactants. For example, if the balanced equation for a reaction is: 2 AgI + Na 2 S → Ag 2 S + 2 NaI

When are there more than two reactants in a reaction?

Note, if there are more than two reactants, one will be a limiting reactant and the others will be excess reactants. In an ideal world, you could simply use the reaction to identify the limiting and excess reactant.

Which is the limiting reactant when more is required?

If more is required, then B is the limiting reactant. If less is required, then A is the limiting reactant. You compare the calculated amount of B to the actual amount available. If more is required, then A is the limiting reactant. If less is required, then B is the limiting reactant.

When to use solubility and excess reactant in chemistry?

Solubility and Excess Reactant . In an ideal world, you could simply use the reaction to identify the limiting and excess reactant. However, in the real world, solubility comes into play. If the reaction involves one or more reactants with low solubility in a solvent, there’s a good chance this will affect the identities of the excess reactants.